Remote-controlled video cameras
Both CCTV and IP cameras are available with PTZ (Pan/Tilt/Zoom) functions allowing surveillance equipment operators to control systems remotely. When installed in stations or terminals, analogue PTZ systems can be advantageous because video processing is done at the monitoring station rather than on the camera, as in IP systems. Due to this, video is transferred immediately providing real-time viewing and accurate remote movement control functions. In IP systems source video processing can result in an inherent lag in video streaming meaning that camera control can be more difficult for the operator. For the application of either analogue or digital systems in vehicles, achieving real-time remote monitoring and control can be problematic. The requirement for on-board processing and recording, as well as the potential for signal or transmission interruption, can render continuous real-time monitoring and remote control almost impossible when publically accessible mobile network solutions are used. As such PMR solutions, while more expensive, are much more preferable when real-time monitoring is a necessity. This though may not hold true for much longer as constant improvements in the mobile network are providing better continuous coverage and higher data transfer speeds.
A key consideration in mobile surveillance applications is the required spatial coverage. It may not be necessary to use a PTZ system in enclosed environments as a static camera may provide adequate image quality and area coverage. As such, PTZ cameras are likely to be more suited to on-street or in-station applications rather than in-vehicle. In addition to this, video management software allows for analysis, including zoom functions, of recorded video, which may be all that is needed provided image quality is good enough. PTZ systems are also more expensive and consume more power than static surveillance equipment, and these additional costs may not need to be incurred.
Another function available on some camera systems is real-time video streaming control from the driver console. Where video surveillance systems are integrated with wireless radio equipment capable of real-time data transfer, the driver can select when to stream video to a control centre via button mounted on the driver console. This may allow for reduced storage requirement if cameras are only used when requested, however this may lead to events being missed if the driver does not react fast enough. A better solution may be to use cameras with motion sensors which go to a stand-by mode when there is no activity. This also reduces storage capacity requirement as well as energy consumption. Motion sensor equipment is widely available and not generally a significant additional expense.
- Operations management
Benefits and cautions
PTZ systems are more expensive in terms of initial cost and energy costs than static cameras. As such a key consideration in choosing these systems is the area that actually requires monitoring. If it is an enclosed space and a static camera could provide high enough image quality then these are likely to be a better solution.
The choice between analogue CCTV or digital IP PTZ is the same as the choice between analogue and digital systems generally. Analogue systems are a more developed technology but do not tend to have the same level of functionality as digital systems. Remote monitoring in-vehicle however, may be easier to facilitate with digital systems and image quality tends to be better. For these reasons these cameras are potentially a better solution on-board vehicles particularly when remote control is necessary.
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